

Gastric Sleeve Surgery
The most popular weight-loss operation around the world.
Gastric sleeve surgery, also known as sleeve gastrectomy, is where 75% of the stomach is permanently removed and seam-guarded, leaving a thin tube or sleeve.
It works by reducing the amount of food you can eat and reducing your appetite.
Benefits of Sleeve Gastrectomy
Having gastric sleeve surgery helps many people who previously struggled with weight loss to take back control and live a happier, healthier life.
A gastric sleeve has the added benefit of removing the upper part of your stomach (the part that produces the hunger hormone, ghrelin).
Without this part of your stomach, you’ll be less hungry and will feel fuller, sooner.
Benefits of gastric sleeve surgery include:
Is a Gastric Sleeve Right for Me?
If you have already tried adjusting your diet and exercise routine to lose weight and these measures have not been effective, you may qualify for a gastric sleeve. The sleeve gastrectomy is generally not advised for those with conditions such as acid reflux, Barrett’s oesophagus and oesophageal dysmotility.
Gastric sleeve surgery works by removing 75% of the stomach, leaving a thin tube or sleeve.
Gastric sleeve surgery, also known as sleeve gastrectomy, is a weight-loss procedure that involves reducing the size of the stomach to promote weight loss. It is carried out laparoscopically (keyhole surgery) under a general anaesthetic. The sleeve also impacts the release of hormones that boost weight loss and, in some cases, helps improve obesity-related medical problems such as diabetes and high blood pressure.
Here’s a breakdown of how it works:
1. Reduction of the stomach
During the surgery, about 75-80% of the stomach is removed, leaving a tube-like structure that resembles a “sleeve”. The remaining stomach is much smaller, which significantly reduces the amount of food it can hold.
2. Restriction of food intake
With a smaller stomach, patients feel full more quickly after eating smaller portions. This helps reduce overall calorie intake, which is key to weight loss.
3. Hormonal changes
The part of the stomach that is removed also produces a hormone called ghrelin, which stimulates hunger. By removing this portion, the levels of ghrelin decrease, leading to reduced appetite and hunger cravings.
4. Digestive process
The digestive process remains the same as before, meaning the stomach still digests food and absorbs nutrients normally. This makes sleeve gastrectomy different from some other procedures like gastric bypass, which alters the digestive pathway.
5. Weight loss
Patients typically experience significant weight loss in the months following surgery due to both reduced food intake and hormonal changes. It’s usually performed as part of a broader weight-loss strategy that includes diet, exercise, and lifestyle changes.
Gastric sleeve surgery is considered irreversible, and it’s often recommended for individuals who are severely obese and haven’t been able to achieve sustained weight loss through other methods.
The gastric sleeve procedure usually takes between two and four hours and is performed under general anaesthetic.
1. Surgical process
Incision and access
The surgery is typically performed laparoscopically, which means it’s done through several small incisions (around 5) rather than one large incision. The surgeon inserts a laparoscope (a small camera) and surgical instruments through these incisions.
Visualisation and isolation
The surgeon inflates the abdomen with carbon dioxide gas to create space and visibility to access the stomach. The stomach is carefully separated from surrounding tissues such as the spleen and blood vessels using specialised instruments.
Stomach resection
About 75-80% of the stomach is removed along the greater curvature (the larger outer portion). This is done by stapling along the length of the stomach using a specialised stapler that seals the stomach to prevent leaks.
The new stomach is shaped like a narrow tube or “sleeve,” which will hold far less food than before.
Reinforcement of staple line
Some surgeons reinforce the stapled area with sutures or a synthetic material to reduce the risk of leakage or bleeding along the staple line.
2. Removal of the stomach portion
Extraction
The removed portion of the stomach is extracted through one of the incisions. This part of the stomach is no longer functional, and its removal reduces the overall capacity of the stomach.
3. Closure and monitoring
Closure of incisions
Once the stomach is resized and the resection is complete, the small incisions are closed with sutures or surgical glue.
Leak test
Before completing the procedure, the surgeon may conduct a “leak test” to ensure that the staple line is intact. This is done by injecting a small amount of fluid or air to check for leaks.
Drain placement
Some surgeons place a temporary surgical drain near the stomach to help remove any excess fluid during the recovery phase. This drain is usually removed within a few days after surgery.
70-75% of excess weight lost
At twelve months, gastric sleeve patients can expect to lose approximately 70–75% of their excess weight (a term used to describe weight above a BMI of 25).
Typically, that’s 25–30% total body weight over a period of nine to twelve months.
Gastric sleeve surgery is considered a non-reversible procedure as we are removing a part of the stomach. This helps patients achieve long-term sustained weight loss.
Back on your feet in no time
The average postoperative hospital stay from gastric sleeve surgery is one to two days, with an enhanced recovery programme.
Patients can expect to be up and walking within three hours of surgery, drinking the same day, and returning to work and normal activities within seven days.
After the operation, patients will be advised to go on a specialist diet to help with the healing process.
This involves a liquid diet for two weeks, a puréed diet for one to two weeks and eating soft, easy-to-chew foods for one to two weeks. The first follow-up appointment after the sleeve is usually six to eight weeks after the operation. In this session, the surgeon will advise on progress and ensure there are no immediate problems.
Patients will be eating smaller portion sizes and so they will need to take supplements to reduce the risk of vitamin and mineral deficiencies following surgery. Patients will require lifelong calcium (with vitamin D), iron and multivitamins, as well as three-monthly vitamin B12 injections. Blood tests are recommended every six to twelve months to ensure adequate supplementation. Alternatively, patients can take all-in-one supplements. (Tonic’s equivalent is VitMyLife.)
Preparing for a gastric sleeve
To prepare for the sleeve gastrectomy, patients will have a consultation with their surgeon and will be assessed by the Tonic team, including the dietitian, psychotherapist and bariatric nurse specialists.
You’ll undergo a comprehensive evaluation, which may include blood tests and imaging studies.
You will be asked to go on a liver-shrinking diet (800 calories a day), for around two weeks before surgery.
After your operation, you’ll be taken to a recovery area, where our healthcare team will carefully monitor your blood pressure and heart rate.
You will be given pain relief, and you may have small drains in your wounds to remove excess fluid, along with a catheter to drain urine from your bladder.
These will all be removed before you leave the hospital. Once you’re moved to a ward, you’ll be encouraged to slowly start moving around.
For the remainder of your stay, you’ll be on a liquid-only diet, and it’s normal for your stomach to feel sore or bruised. Let us know if you experience any discomfort. The duration of your stay will vary depending on your recovery, so please discuss your discharge plan with your consultant.
You will not be able to drive after your surgery, so please arrange for someone to take you home when you’re discharged.
Gastric sleeve surgery works by removing 75% of the stomach, leaving a thin tube or sleeve.
Gastric sleeve surgery, also known as sleeve gastrectomy, is a weight-loss procedure that involves reducing the size of the stomach to promote weight loss. It is carried out laparoscopically (keyhole surgery) under a general anaesthetic. The sleeve also impacts the release of hormones that boost weight loss and, in some cases, helps improve obesity-related medical problems such as diabetes and high blood pressure.
Here’s a breakdown of how it works:
1. Reduction of the stomach
During the surgery, about 75-80% of the stomach is removed, leaving a tube-like structure that resembles a “sleeve”. The remaining stomach is much smaller, which significantly reduces the amount of food it can hold.
2. Restriction of food intake
With a smaller stomach, patients feel full more quickly after eating smaller portions. This helps reduce overall calorie intake, which is key to weight loss.
3. Hormonal changes
The part of the stomach that is removed also produces a hormone called ghrelin, which stimulates hunger. By removing this portion, the levels of ghrelin decrease, leading to reduced appetite and hunger cravings.
4. Digestive process
The digestive process remains the same as before, meaning the stomach still digests food and absorbs nutrients normally. This makes sleeve gastrectomy different from some other procedures like gastric bypass, which alters the digestive pathway.
5. Weight loss
Patients typically experience significant weight loss in the months following surgery due to both reduced food intake and hormonal changes. It’s usually performed as part of a broader weight-loss strategy that includes diet, exercise, and lifestyle changes.
Gastric sleeve surgery is considered irreversible, and it’s often recommended for individuals who are severely obese and haven’t been able to achieve sustained weight loss through other methods.
The gastric sleeve procedure usually takes between two and four hours and is performed under general anaesthetic.
1. Surgical process
Incision and access
The surgery is typically performed laparoscopically, which means it’s done through several small incisions (around 5) rather than one large incision. The surgeon inserts a laparoscope (a small camera) and surgical instruments through these incisions.
Visualisation and isolation
The surgeon inflates the abdomen with carbon dioxide gas to create space and visibility to access the stomach. The stomach is carefully separated from surrounding tissues such as the spleen and blood vessels using specialised instruments.
Stomach resection
About 75-80% of the stomach is removed along the greater curvature (the larger outer portion). This is done by stapling along the length of the stomach using a specialised stapler that seals the stomach to prevent leaks.
The new stomach is shaped like a narrow tube or “sleeve,” which will hold far less food than before.
Reinforcement of staple line
Some surgeons reinforce the stapled area with sutures or a synthetic material to reduce the risk of leakage or bleeding along the staple line.
2. Removal of the stomach portion
Extraction
The removed portion of the stomach is extracted through one of the incisions. This part of the stomach is no longer functional, and its removal reduces the overall capacity of the stomach.
3. Closure and monitoring
Closure of incisions
Once the stomach is resized and the resection is complete, the small incisions are closed with sutures or surgical glue.
Leak test
Before completing the procedure, the surgeon may conduct a “leak test” to ensure that the staple line is intact. This is done by injecting a small amount of fluid or air to check for leaks.
Drain placement
Some surgeons place a temporary surgical drain near the stomach to help remove any excess fluid during the recovery phase. This drain is usually removed within a few days after surgery.
70-75% of excess weight lost
At twelve months, gastric sleeve patients can expect to lose approximately 70–75% of their excess weight (a term used to describe weight above a BMI of 25).
Typically, that’s 25–30% total body weight over a period of nine to twelve months.
Gastric sleeve surgery is considered a non-reversible procedure as we are removing a part of the stomach. This helps patients achieve long-term sustained weight loss.
Back on your feet in no time
The average postoperative hospital stay from gastric sleeve surgery is one to two days, with an enhanced recovery programme.
Patients can expect to be up and walking within three hours of surgery, drinking the same day, and returning to work and normal activities within seven days.
After the operation, patients will be advised to go on a specialist diet to help with the healing process.
This involves a liquid diet for two weeks, a puréed diet for one to two weeks and eating soft, easy-to-chew foods for one to two weeks. The first follow-up appointment after the sleeve is usually six to eight weeks after the operation. In this session, the surgeon will advise on progress and ensure there are no immediate problems.
Patients will be eating smaller portion sizes and so they will need to take supplements to reduce the risk of vitamin and mineral deficiencies following surgery. Patients will require lifelong calcium (with vitamin D), iron and multivitamins, as well as three-monthly vitamin B12 injections. Blood tests are recommended every six to twelve months to ensure adequate supplementation. Alternatively, patients can take all-in-one supplements. (Tonic’s equivalent is VitMyLife.)
Preparing for a gastric sleeve
To prepare for the sleeve gastrectomy, patients will have a consultation with their surgeon and will be assessed by the Tonic team, including the dietitian, psychotherapist and bariatric nurse specialists.
You’ll undergo a comprehensive evaluation, which may include blood tests and imaging studies.
You will be asked to go on a liver-shrinking diet (800 calories a day), for around two weeks before surgery.
After your operation, you’ll be taken to a recovery area, where our healthcare team will carefully monitor your blood pressure and heart rate.
You will be given pain relief, and you may have small drains in your wounds to remove excess fluid, along with a catheter to drain urine from your bladder.
These will all be removed before you leave the hospital. Once you’re moved to a ward, you’ll be encouraged to slowly start moving around.
For the remainder of your stay, you’ll be on a liquid-only diet, and it’s normal for your stomach to feel sore or bruised. Let us know if you experience any discomfort. The duration of your stay will vary depending on your recovery, so please discuss your discharge plan with your consultant.
You will not be able to drive after your surgery, so please arrange for someone to take you home when you’re discharged.
5 Steps to Change Your Life
Disclaimer
As with any surgical procedure, there are possible risks and complications, including bruising, pain & bleeding, infection, nausea & vomiting, oesophagitis (inflammation of the oesophagus) or gastritis (inflammation of the stomach), bowel rupture/leakage, scarring, stricture or narrowing of the sleeve so food can’t pass through, intolerance to certain foods, gastroesophageal reflux disease (GERD) with severe heartburn, dumping syndrome, internal injury to your organs during surgery and leaking from the staples, pulmonary embolism (clot to the lung), deep vein thrombosis and death. These are uncommon and we will do everything possible to prevent them from happening. One in ten patients may experience acid reflux symptoms and require PPI (anti-acid) tablets (though this would be expected to improve or resolve in most patients as the sleeve and eating habits mature over one to two years). The sleeve gastrectomy may also be associated with developing Barret’s oesophagus.
Patients may require plastic surgical procedures after weight loss has levelled off, to treat loose skin.
Patients may develop symptomatic gallstones after weight loss, which would require a laparoscopic cholecystectomy.
If you do not reach the expected weight loss after surgery, your surgeon can explain the alternative interventions or revisions available.
Please speak to your Tonic surgeon to discuss the risks in more detail and any concerns you may have.
Read more >Chanelle Hayes’ Tonic Weight Loss Journey
“I had gastric sleeve surgery with Tonic. I’ve lost 9 stone and feel amazing! It has completely turned my life around and given me and my children a second chance to create memories and have fun together.”

Hi I'm Sarah Ash
I’m a Tonic Patient Coordinator; I’m here to help you start your weight loss journey.
It’s my job to support you through your journey with Tonic, from initial consultation where we’ll learn all about you and your weight loss journey to date, through to your 5 years of aftercare with our specialist team.
We’re here for you at every stage.
Which Weight Loss Surgery is Right for You?
We offer a wide variety of weight loss surgeries; we’ll never recommend a surgery unless it’s 100% right for you.
Compare our available surgeries here:
Gastric Bypass
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Allurion Pill Balloon
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Gastric Sleeve
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Mini Gastric Bypass
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Gastric Band
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Average recovery time after surgery
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10-14 Days
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2-3 Days
|
7 days
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10-14 Days
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5-7 Days
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Surgery procedure time (in minutes)
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60 mins
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0 mins
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60 mins
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70 mins
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45 mins
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Estimated weight loss
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60 - 70% Excess Weight Loss
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20% Excess Weight Loss
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70–75% of their excess weight
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60 - 70% Excess Weight Loss
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50 - 70% Excess Weight Loss
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Tonic premium aftercare
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Included ![]() |
Included ![]() |
Included ![]() |
Included ![]() |
Included ![]() |
Scarring?
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5 x Small (12mm) abdominal incisions across the middle and upper abdomen
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No
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5 small abdominal scars
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5 x Small (12mm) abdominal incisions across the middle and upper abdomen
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5 x Small (12mm) abdominal incisions across the middle and upper abdomen
|
Read more | Read more | Read more | Read more | Read more |
Disclaimer for all Weight Loss and Bariatric Procedures
Weight loss surgery results may vary: causes for being overweight or obese vary from person to person.
Gastric Sleeve Surgery FAQs with Bariatric Surgeon Sherif Awad
Learn more about gastric sleeve surgery, directly from leading bariatric surgeon, Sherif Awad.
Want to ask questions directly to our specialists?
PREMIUM AFTERCARE A TONIC PROMISE
No Other Provider Offers Aftercare Like Tonic
We pride ourselves in providing the most comprehensive support package around you after your procedure.
Weight loss surgery is a tool to help you lose weight. Our aftercare team is composed of nurses, psychotherapists, personal trainers, bariatric surgeons and other weight loss specialists. It’s our job to ensure your weight loss journey goes as smoothly as possible.
You will not get 5 years of aftercare included with your surgery anywhere else.
Full aftercare breakdownUnlimited Dietician Support for 2 years
Unlimited Psychotherapist Support for 2 years
Unlimited Support with Virtual Fitness Coach for 2 Years
Unlimited Bariatric Nurse Support for 2 years
5 Years Surgeon Follow Up
The Gym Group 30-day Membership
The Tonic Tool Kit
Tonics Private Social Media community support
Out Of Hours Support Line
Our Clinic Locations
Private Weight Loss Surgery Clinics and Bariatric Surgery Specialists Located Across the UK
Wherever you are in the UK, we have weight loss specialists year you.
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